Question

Children suffering from phenylketonuria are given food low in phenylalanine and supplemented with tyrosine. This is because they:

• A. Are unable to utilize phenylalanine
• B. Do not require phenylalanine
• C. Have increased tyrosine anabolism
• D. Have increased tyrosine catabolism

Answer 1

The correct option is A

Are unable to utilize phenylalanine

Phenylketonuria is an autosomal recessive disorder with mutation in gene for enzyme phenylalanine hydroxylase (PAH), rendering it non functional.
Phenylalanine $\stackrel{PAH}{\to }$ Tyrosine
Such person cannot metabolise the above reaction leading to accumulation of phenylalanine. So, children suffering from phenylketonuria are given food low in phenylalanine and supplemented with tyrosine.